Water intrusion into the passenger side front behind & to the right of the glove box has nothing to do with the battery itself, but it has everything to do with your problem If you got your BCM (Body Control Module) wet from your plugged sunroof drains, it then shorts out, drains the battery, and freaks out the body electrical. Think of it like getting your cell phone wet, maybe the first time you get lucky and it keeps working (for a while), next time or two it gets wet = toast.

Search the fix for leaking sunroof drains, get that taken care of. When the water stops, and your BCM is 100% dry, then see what problem is left behind.